Genomic analysis of a novel high-risk ST5217/ExoU+/O11 clone of carbapenem-resistant OXA-181- and VIM-2-producing Pseudomonas aeruginosa in India.

OBJECTIVES

Studies of carbapenem-resistant Pseudomonas aeruginosa (CRPA)-harbouring OXA-48-like carbapenemases are rare. The study aimed to report the emergence and characterization of a novel high-risk clone of CRPA-harbouring OXA-48-like from India.

METHODS

Identification, AST, phenotypic detection of carbapenemases and WGS using Ion-Torrent-S5 platform were carried out. Analyses included ResFinder, VFDB, MLST, PAst, Phastest and CRISPR/Cas. SNP-based phylogenetic analysis with global OXA-48-like-harbouring CRPA genomes was carried out by CSI Phylogeny and iTOL for visualization.

RESULTS

The clinical MDR strain of CRPA AMRIR00655 belonged to a novel sequence type ST5217 and serotype O11. Phenotypic tests followed by WGS revealed the presence of dual carbapenemases, OXA-181 (serine-carbapenemase) and VIM-2 (zinc-carbapenemase), both located on chromosome. blaOXA-181 resides between chromosomal genes encoding RodZ and PAP2 in P. aeruginosa, confirming chromosomal integration.4,261 bp of blaOXA-181-bearing contig-DNA showed 100% homology to K. pneumoniae plasmid pKP3-A. ISEcp1 was present on upstream and on downstream, △lysR, △ereA and repA genes were detected. blaVIM-2 was located within class 1 integron along with aacC6-II, dfrB5, aac(3)-Id, tniC in surrounding regions and 13,242 bp showing 100% identity to P. aeruginosa chromosome. Presence of other ARGs (blaPAO, blaOXA-488,aph(3'')-Ib, aph(6)-Id, crpP, catB7, fosA, sul2) and efflux-pump genes might explain its MDR phenotype. Virulence factors including T3SS (PscF, PopB, PopD, PcrV) and its effectors (ExoT, ExoU, ExoY) indicated the pathogenic potential of ST5217. Core genome analysis showed that ST5217 was closest with other high-risk clones ST1339 and ST773-harbouring blaOXA-48-like.

CONCLUSIONS

To the best of our knowledge, this is the first report of blaOXA-181-harbouring novel high-risk clone of CRPA ST5217/ExoU+/O11 in India which emphasises the spread of OXA-181 among bacteria other than Enterobacteriaceae-family and warrant close monitoring.